Gas seals for fluid flow machines, especially compressors which are designed as turbomachines, are the preferred form of seal in the case of higher pressures as a result of the comparatively low leakage. For example, in comparison to conventional labyrinth seals the lower leakage of the dry gas seal enables by an order of magnitude a significant efficiency increase of the corresponding turbomachine.
Compared with the relatively simply constructed labyrinth seals, modern dry gas seals are comparatively demanding with regard to operating conditions. A reliable operation of dry gas seals is only possible if a slide film of dry gas between the two sealing rings is constantly supplied with gas in proportion to high process quality. The gas for the supplying of the gas film between the sealing rings has to be sufficiently dried on the one hand and on the other hand has also to be relatively free of foreign bodies. The auxiliary systems, for example of a process gas compressor, which are required for the gas treatment can definitely lie within the order of magnitude of the actual compressor with regard to their space requirement and the investment costs.
Shaft seal arrangements, which as a result of their principle of operation are dependent upon a high processing quality of the seal gas, are known from DE 690 19 296 T2, DE 692 04 703 T2, DE 693 03 749 T2, U.S. Pat. No. 5,222,743 A1 and U.S. Pat. No. 6,152,452 A1 respectively. From the search in relation to DE 10 2012 214 276.2, documents DE 19 64 150 A, DE 202 16587 U1, US 2003/0 209 859 A1, U.S. Pat. No. 6,341,782 B1, DE 17 75 596 A, DE 2618682 A1, DE 38 39 106 A1, DE 29 28 504 A1 and EP 1 275 864 A1, which also deal with shaft seals, are already known. Those, which focus on gas seals thereof, are dependent on a high processing quality of the seal gas and are regularly tied to direction of rotation.